coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer() (CVE-2026-64402) | HOL Guard CVE

High · CVSS 7.8CVE-2026-64402

coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer()

Answer in brief

CVE-2026-64402 records a High severity (CVSS 7.8) vulnerability in coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 25, 2026Updated Sep 4, 2026Source checked Sep 20, 2026First seen by HOL Aug 5, 2026Material review Sep 4, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.8
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:o:linux:linux_kernel::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <38dbc8db8341ccdf8e1e1a067453d33ad751864b \|\| >=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <4c5a0a946373da99a80398289b28845b5ae40cd1 \|\| >=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb \|\| >=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f \|\| >=06f5c2926aaa0fba7f99678da6ef77cbbbda1441 <98495b5a4d77dd22e106f462b76e1093a55b29a7	38dbc8db8341ccdf8e1e1a067453d33ad751864b, 4c5a0a946373da99a80398289b28845b5ae40cd1, 661a019ac0413ecec9e5d1dfcc12fbca8e78d5fb, daf6246ab988fc8bdc82ad7c8d0b1c182d11b15f, 98495b5a4d77dd22e106f462b76e1093a55b29a7
Linux/Linuxgeneric	6.3	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 38dbc8db8341ccdf8e1e1a067453d33ad751864b if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 5, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: coresight: ultrasoc-smb: Fix OOB write in smb_sync_perf_buffer() When the SMB sink is used as a perf AUX sink, smb_update_buffer() calls smb_sync_perf_buffer() to copy hardware trace data into the perf AUX ring buffer pages. It derives pg_idx = head >> PAGE_SHIFT from @head, which is handle->head, and indexes dst_pages[pg_idx]. The pg_idx %= nr_pages normalization is only applied after the first loop iteration. This leaves the initial page index underived from the buffer size, which can result in an out-of-bounds write past dst_pages[] when head exceeds the AUX buffer size. Normalize head modulo the AUX buffer size before deriving the page index and offset, mirroring tmc_etr_sync_perf_buffer().

Quoted source text, attributed separately from HOL analysis.